In general, a vehicle uses engine oil for lubrication to smoothly maintain a reciprocating motion of a piston performed in response to an explosion in an engine, for sealing to prevent pressure from being leaked, for anticorrosion to absorb foreign matter in a cylinder to prevent an inner wall of the cylinder from being damaged, and for cooling to absorb heat from the cylinder and the piston.
The engine oil having the above functions is combusted by explosion in the engine over long term use, and thus, the amount of the engine oil may be reduced and the engine oil may deteriorate, such that viscosity, a total acid number, and a sludge amount of the engine oil may change.
Therefore, the engine oil needs to be periodically replenished or exchanged. However, when a vehicle is driving in a state when the oil should be replenished and exchanged, durability of each lubricating part may be degraded, such that engine life and engine output may be reduced. In particular, environmental problems may occur due to excessive fuel consumption and an increased amount of exhaust gas.
To solve the above problems, the related art has used an oil level switch. The oil level switch detects the storage amount of lubricating oil of an engine and informs the user of the detected storage amount of the lubricating oil.
In a case of a hybrid diesel engine, when a driving mode of a vehicle is a hybrid driving mode, the engine is turned off in an ignition on (IG ON) state.
If the oil level switch detects a lack of oil while the driving mode is an engine driving mode and performs a fault diagnose, the vehicle changes to the hybrid driving mode and the engine stops running. Thus, the oil moves back to a lower portion of an oil pan of the engine even though the engine oil is not fully refilled. In this case, the oil level is misdiagnosed to be normal.
The contents described as the related art have been provided only for assisting in the understanding for the background of the present disclosure and should not be considered as corresponding to the related art known to those skilled in the art.